package counter

import (
	"bufio"
	"io"
	"sort"
)

const maxLineSize = 1024 * 1024

type Result struct {
	Name  string
	Count int
}

func Count(r io.Reader) (map[string]int, error) {
	counts := make(map[string]int)

	scanner := bufio.NewScanner(r)
	scanner.Buffer(make([]byte, 64*1024), maxLineSize)

	for scanner.Scan() {
		name := scanner.Text()
		if name == "" {
			continue
		}

		counts[name]++
	}

	if err := scanner.Err(); err != nil {
		return nil, err
	}

	return counts, nil
}

func Sorted(counts map[string]int) []Result {
	results := make([]Result, 0, len(counts))
	for name, count := range counts {
		results = append(results, Result{Name: name, Count: count})
	}

	sort.Slice(results, func(i, j int) bool {
		if results[i].Count != results[j].Count {
			return results[i].Count > results[j].Count
		}

		return results[i].Name < results[j].Name
	})

	return results
}